Chronic aspiration shifts the immune response from adaptive immunity to innate immunity in a murine model of asthma.

Objective And Design: The hypothesis that aspiration of gastric fluid drives the anti-ovalbumin response toward a Th2 reaction even in animals not prone to Th2 responses was evaluated.

Subjects: Forty-eight male C57BL/6 mice were used.

Methods: Mice were sensitized and challenged with ovalbumin starting 5 weeks prior to the initiation of weekly aspirations of either gastric fluid or normal saline as a control.

Lymphocyte phenotypes in wild-caught rats suggest potential mechanisms underlying increased immune sensitivity in post-industrial environments.

The immune systems of wild rats and of laboratory rats can been utilized as models of the human immune system in pre-industrial and post-industrial societies, respectively. In this study, lymphocyte phenotypes in wild rats were broadly characterized, and the results were compared to those obtained by us and by others using cells derived from various strains of laboratory rats. Although not expected, the production of regulatory T cells was not apparently different in wild rats compared to laboratory rats.

Spontaneous bacterial cell lysis and biofilm formation in the colon of the Cape Dune mole-rat and the laboratory rabbit.

A wide range of techniques, including high-throughput DNA sequencing methods, have been applied to the evaluation of the normal intestinal flora. However, the inability to grow many of those species in culture imposes substantial constraints on the techniques used to evaluate this important community. The presence of biofilms in the normal gut adds further complexity to the issue.

Cultivation of epithelial-associated microbiota by the immune system.

Mounting evidence supports the intuitive idea that many of the factors produced in defense of the epithelial surface, including mucin and secretory IgA, promote the growth of the commensal microbial flora, much the same as plant-derived mucoid substances support the growth of symbiotic microbes in the rhizosphere associated with roots. Thus, the 'defense' of the host epithelial surface often involves support and maintenance of microbial growth, despite an unfortunate tendency to view the immune system as an antagonist to the microbial flora. The perspective that the immune system supports the growth of a symbiotic microbiota has the potential to push forward our understanding of host-microbe interactions and to facilitate the development of new treatments for diseases associated with the microbiota.

Gastroesophageal reflux-associated aspiration alters the immune response in asthma.

Background: A large number of studies point toward chronic aspiration associated with gastroesophageal reflux disease (GERD) as an important factor involved in the development of asthma, the incidence of which has increased dramatically in industrially developed countries. Recent work suggests that medical intervention aimed at acid blockade is not sufficient to relieve the effects of chronic aspiration on asthma pathology, leaving surgical treatment of the disease as one of the few remaining options. This study examined the effect of chronic aspiration on the airway-associated immune response to allergens using a model of experimentally induced airway hypersensitivity in Balb/c mice.

Altering and assessing persistence of genetically modified E. coli MG1655 in the large bowel.

One of the primary factors limiting the efficacy of probiotic therapies is short persistence time. Utilizing a novel method for assessment of persistence in the large bowel independent of survival of the organisms in the upper GI tract, we tested whether overexpression of the type 1 pilus, a colonization factor, or the presence of secretory immunoglobulin A (sIgA) might increase the persistence time of a laboratory strain of E. coli in the gut.

Macrophage activation by gastric fluid suggests MMP involvement in aspiration-induced lung disease.

Asthma occurs in more than 5% of the population in industrialized countries and is now characterized as a chronic inflammatory disease. The chronic aspiration of gastric fluid is considered by many investigators to be a primary inflammatory factor exacerbating or predisposing patients to asthma, with more than 50 medical papers per year linking asthma with gastroesophageal reflux disease (GERD), which can lead to aspiration events. However, the mechanisms involved in the inflammatory effects caused by gastric-fluid aspiration are not clear at the present time.